of Cancer , and on Animal Hepatic Air . 405 
changed into the vitriolic acid, and the muriated barytes would 
have been decompofed, 
I frequently repeated the preceding experiment with the air 
extricated, by diftillation, from the putrid as well as from the 
frefh mufcular fibres of animals 5 but I could not, in any 
inftance, difcover the leaf!: veftige of the vitriolic acid. 
The following experiments were made with a view more accu- 
rately to analyfe the airs which are difengaged from animal fob- 
ftances by heat, and to determine the products refulting from 
the union of thefe fluids with pure air. 
About an ounce of the lean of frefh mutton was introduced 
into a frnall coated glafs retort, and expofed to a red heat. The 
air that was extricated towards the end of the diftillation was 
received over mercury; and foon after its production, being 
agitated with water, very nearly one half of it was abforbed. 
A fimilar experiment being made with the air difengaged 
towards the middle of the diftillation, the part of it which 
was folublein water was found to be to the part not folublein 
that fluid as 2 to 3. Having buffered a feparate portion of the 
air difengaged towards the end of the diftillation to remain over 
mercury for feven hours, it was found gradually to diminifh ia 
bulk, and a fluid, which had the colour and the odour of a thin 
empyreumatic oil, was collected at the bottom of the jar *. The 
air being now agitated with water, only one-eighth of it was 
abforbed. Hence it appears, that a portion of the air, extri- 
cated from animal fubftances by heat, refembles a fpecies of 
hepatic air which was flrft difcovered by Mr. Kirwan, and 
which exifts in ail -intermediate ftate between the aerial and 
the vaporous ; this fluid not being permanently elaftic like 
* The above-mentioned appearance is not conffant, The air when placed over 
mercury fometimes diminifties, and at other times it retains its oriHnal bulk. • 
have not as yet difcovered the caufe of this difference. 
